It's impossible to disable images in Firefox

Meta -

OS: Windows Selenium Version: 2.53 Browser: Firefox Browser Version: 46.0.1

Steps to reproduce -

create driver instance using this capabilities

DesiredCapabilities capabilities = new DesiredCapabilities();
FirefoxProfile profile = new FirefoxProfile();
profile.setPreference("permissions.default.image", 2);
capabilities.setCapability("firefox_profile", profile);

Note if I use exist FF profile FirefoxProfile profile = new ProfilesIni().getProfile("existProfile") images are disabled

Expected Behavior -

Images are disabled in broswer

Actual Behavior -

Images aren’t disabled in broswer

[barancev]

FirefoxOptions options = new FirefoxOptions()
    .addPreference("permissions.default.image", 2);
driver = new FirefoxDriver(options);

Works well in Selenium 3.7.0, tested in Firefox 57 + geckodriver 0.19 and Firefox ESR 52 with legacy driver.

[jquacinella]

@lukeis This is super easy to do in chrome. Why is this not able to be done via geckodriver?